the PPC Journal article: "The Volume Label",V14N2 Feb 1987, by Cristian Rusquelles. Requires an Extended I/O module.

 01 LBL "WL"
 02 >"     "    ; append 6 spaces
 03 ASTO 00
 04 LBL 00
 05 AID
 06 16
 07 X=Y?
 08 GTO 01
 09 "NOT A DRIVE"
 10 PROMPT
 11 GTO 00
 12 LBL 01
 13 CLRDEV
 14 3
 15 DEVL
 16 2
 17 OUTXB
 18 6
 19 DEVL
 20 "D"
 21 ARCL 00
 22 OUTAE
 23 8
 24 DEVL
 25 END